1. Field of the Invention
The present invention relates to an electronic device which includes a digital display screen and which is able to receive a radio wave.
2. Description of the Related Art
Conventionally, there is an electronic timepiece (radio-controlled timepiece) which receives a radio wave in a long wavelength band (standard radio wave) including time information and obtains time data to be able to calibrate the held time information. In such radio-controlled timepieces, the present time is calibrated at a predetermined cycle or calibrated based on operation by the user so as to be able to maintain display of accurate time.
In a radio-controlled timepiece, a small antenna for receiving the standard radio wave is provided inside the casing. A bar antenna is preferably used as the small antenna. However, most electronic circuits and electronic components generate noise in a long wavelength band, and the noise from the adjacent wiring and electronic components tend to be mixed when the standard radio wave is received. Specifically, in small radio-controlled timepieces such as watches, the electronic components, wiring and antenna need to be provided closely, and the problem of the noise mixing appears significantly.
In view of the above, Japanese Patent Application Laid-Open Publication No. 2010-273231 discloses a technique where the edge of the substrate is cut to provide a space for the antenna so that there is a distance from the antenna to the wiring and the electronic components on the substrate while maintaining a compact size. Alternatively, Japanese Patent Application Laid-Open Publication No. 2012-58161 describes providing an antenna on the rear face of the edge of the substrate with a shield electrode in between, so that the reception level of the noise decreases.
However, when an electronic device which receives radio waves includes a digital display screen such as a liquid crystal display (LCD), connectors for the output terminal are provided on both edges of the substrate, and the desired display is achieved by driving the voltage of the pixels or the segments of the display screen provided between the connectors. Therefore, if the edge of the substrate is cut as in the technique described in Japanese Patent Application Laid-Open Publication No. 2010-273231, the area of the display screen becomes small in the cut amount. As for the technique described in Japanese Patent Application Laid-Open Publication No. 2012-58161 where the antenna is provided on the rear face of the edge of the substrate, the width of the connector needs to be less than the length of the antenna, and it is not possible to increase the output terminals. Therefore, it is difficult to provide a display screen with a high resolution which includes a large number of output terminals, or a display screen of a dot matrix method.
The present invention is an electronic device which can receive radio waves preferably while setting the size and the resolution of the display screen to a large setting.